Automated well control method and apparatus

Abstract

A drilling control system monitors and compares drilling and completion operation sensor values and autonomously acts in response to conditions such as a kick or surge. Sensors in various combinations may monitor return fluid flow rate, fluid inflow rate, wellhead bore pressure, temperature of returning fluid, torque, rate of penetration and string weight change. The control system has corresponding control logic to monitor, warn and act based on the sensor inputs. The actions may include the warning of support personnel, closing an annular blowout preventer, shearing drill pipe using a ram shear, pumping heavier fluid down choke and kill lines, disconnecting the riser or various other actions.

The invention claimed is: 
     
       1. An apparatus providing for automatic detection and control of a kick during subsea well drilling and completion operations with a rig connected to a subsea wellhead assembly via a riser and blowout preventer (BOP), the BOP having a riser disconnect, the apparatus comprising:
 a plurality of sensors adapted to be coupled to a wellhead assembly for producing current sensor values of a well undergoing operations; 
 a control system having a processor containing a database of known sensor values indicative of a kick event, the processor having means for receiving and the current sensor values from the sensors and comparing the current sensor values against the known sensor values; 
 the control system having an automated warning component that alerts operations personnel if the comparison indicates a kick event; 
 the control system being linked to the BOP to automatically close the BOP if the kick event is still occurring after a selected time period; and 
 the control system being linked to the riser disconnect to automatically begin steps to actuate the riser disconnect if the kick event is still occurring after the BOP has been closed for a selected time period. 
 
     
     
       2. The apparatus according to  claim 1 , wherein the control system further comprises:
 a link to shear rams in the BOP to automatically close the shear rams to shear a string of drill pipe to actuating the riser disconnect in the event the kick is still occurring after the BOP has been closed a a selected time period. 
 
     
     
       3. The apparatus according to  claim 1 , wherein at least one of the sensors comprises:
 a riser inclination sensor, and wherein 
 the control system is linked to the riser inclination sensor to automatically actuate the riser disconnect only if an inclination of the riser does not exceed a maximum inclination. 
 
     
     
       4. The apparatus according to  claim 1 , wherein the sensors comprises:
 a return flow rate sensor adapted to be coupled to a fluid return conduit of the drilling rig; 
 an upward flowing fluid temperature sensor adapted to be coupled to the wellhead assembly; and 
 a wellhead bore pressure sensor adapted to be coupled to the wellhead assembly. 
 
     
     
       5. The apparatus according to  claim 1 , wherein at least one of the sensors comprises:
 an inflow rate sensor adapted to be coupled to an input fluid conduit of the drilling rig. 
 
     
     
       6. The apparatus according to  claim 1 , wherein at least one of the sensors comprises:
 a string weight sensor adapted to be coupled to a top drive of the drilling rig. 
 
     
     
       7. The apparatus according to  claim 1 , wherein at least one of the sensors comprises:
 a rate of penetration sensor adapted to be coupled to a top drive of the drilling rig. 
 
     
     
       8. The apparatus according to  claim 1 , wherein at least one of the sensors comprises:
 a torque sensor adapted to be coupled to the top drive of the drilling rig. 
 
     
     
       9. An apparatus providing for automatic detection and control of a kick during a subsea well drilling and completion operation with a rig connected to a subsea wellhead assembly via a riser and blowout preventer (BOP) having a riser disconnect that disconnects the riser from the BOP, the apparatus comprising:
 a plurality of sensors, including a pressure sensor adapted to be coupled to the wellhead assembly and a return flow rate sensor adapted to be coupled to a fluid return conduit of the drilling rig; 
 a control system having a processor having a database with known ranges of wellhead pressure and return flow rates indicative of a kick event, the processor having means for receiving and comparing signal values from the pressure sensor and the return flow rate sensor against the known ranges and providing a warning to operating personnel in in the event a kick event is detected; 
 the control system being linked to the BOP and having means for closing the BOP automatically around a drill string extending through the riser in response to indications by the processor that the kick event is still occurring selected time period after the warning is provided; 
 the control sytem further means for closing a shear rams of the BOP to shear the drill string extending through the riser in the event the processor indicates the kick event is still occurring a selected time period after the BOP closed; and 
 the control system further having means for actuating the riser disconnect to disconnect the riser from the BOP in the event the processor indicates the kick event is still occurring a selected time period after the drill string has been sheared. 
 
     
     
       10. The apparatus according to  claim 9 , wherein the sensors further comprise:
 a riser inclination sensor linked to the processor; and wherein 
 the control system actuate the riser disconnect only in the event the riser inclination sensed by the processor is less than a maximum riser inclination. 
 
     
     
       11. The apparatus according to  claim 9 , wherein the sensors further comprise:
 an upward flowing fluid temperature sensor adapted to be coupled to the wellhead assembly; 
 an inflow rate sensor adapted to be coupled to an input fluid conduit of the drilling rig; and 
 the control system receives a signal from the upward flowing fluid temperature sensor and the inflow rate sensor for processing. 
 
     
     
       12. The apparatus according to  claim 9 , wherein the sensors further comprise:
 a string weight sensor adapted to be coupled to a top drive of the drilling rig; 
 a rate of penetration sensor adapted to be coupled to a top drive of the drilling rig; 
 a torque sensor adapted to be coupled to the top drive of the drilling rig; and 
 the control system receives a signal from the string weight sensor, the rate of penetration sensor, and the torque sensor for processing. 
 
     
     
       13. A method for providing automatic detection and control of a kick during subsea well drilling and completion operations with a rig connected to a subsea wellhead assembly via a riser and blowout preventer (BOP), comprising:
 coupling sensors to the wellhead assembly and various components of the rig to indicate conditions within the well; 
 providing a control system with a database of known sensor values that may be indicative of a pressure kick, and linking the control system to the sensors; 
 with the control system, determining the existence of a kick event by comparing the known sensor values to current sensor values received from the sensors; 
 automatically alerting operations personnel when a kick event is detected; then 
 with the control system,continuing to determine wheather the kick event is still occurring for a selected time period, then if so, automatically closing the BOP with the control system to control the kick; then 
 with the control system, continuing to determine whether the kick event is still occurring for a a selected time period after closing the BOP, and, if so, automatically taking steps to disconnect the riser from the BOP with the control system. 
 
     
     
       14. The method according to  claim 13 , wherein:
 automatically taking steps to disconnect the riser from the BOP comprises automatically closing shear rams of the BOP around a drill string extending through the riser and BOP into the well; then 
 with the control system automatically shearing the drill string with the shear rams, alerting operation personnel that the drill string has been sheared and continuing to determine whether the the kick event is still occurring. 
 
     
     
       15. The method according to  claim 13 , wherein:
 automatically taking steps to disconnect the riser from the BOP comprises automatically closing shear rams of the BOP around a drill string extending through the riser and BOP into the well; then 
 with the control system, automatically shearing the drill string with the shear rams, alerting operation personnel that the drill string has been sheared and continuing to determine whether the kick event is still occurring; then 
 if the conrol system determine the kick event is still occurring after a selected time period, with the contol system, automatically disconnecting the riser string from the BOP. 
 
     
     
       16. The method according to  claim 13 , wherein:
 coupling sensors to the wellhead assembly and various components of the rig comprises coupling a pressure sensor to the wellhead assembly. 
 
     
     
       17. The method according to  claim 13 , wherein:
 coupling sensors to the wellhead assembly and various components of the drilling rig comprises coupling a return flow rate sensor to a fluid return conduit of the drilling rig. 
 
     
     
       18. The method according to  claim 13 , wherein:
 coupling sensors to the wellhead assembly and various components of the drilling rig comprises coupling a return flow rate sensor to a fluid return conduit of the drilling rig and an inflow rate sensor to an input fluid conduit of the drilling rig. 
 
     
     
       19. The method according to  claim 13 , wherein:
 coupling sensors to the wellhead assembly and various components of the drilling rig comprises coupling a string weight sensor, a rate of penetration sensor, and a torque sensor to a top drive of the drilling rig. 
 
     
     
       20. The method according to  claim 15 , wherein:
 coupling sensors to the wellhead assembly and various components of the drilling rig comprises coupling a riser inclination sensor to the drilling rig; and 
 wherein the control system automatically disconnects the riser from the BOP only if an inclination of the riser does not exceed a maximum inclination.